Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Stable Isotope Dilution Analysis
Diagnosing individuals with potential increased risk factors for coronary artery disease. A functional assay for folic acid deficiency. Diagnosing homocystinuria. Plasma is the preferred specimen for cardiovascular risk factor and folate functional test. Patients with reduced renal function should be evaluated by quantitating homocysteine in the urine.
0 - 9 mcmol/g creatinine
Homocysteine values and their relationship to coronary artery disease are still investigative.
2 - 5 days
- HOMOCYSTEINE, TOTAL, URINE
Collect random urine specimen as follows: Discard first morning urine void following an overnight fast. Continue fasting and collect the next urine void. Place specimen on ice until it can be frozen. Store and transport frozen.
Large quantities of homocysteine are excreted in urine of patients with homocystinuria due to: Cystathionine-beta-synthetase deficiency, aberrrant B12 metabolism, or N-5,10-methylene-tetrahydrofolate reductase deficiency (many of the patients with this deficiency respond to folic acid supplementation). Folic acid deficiency is characterized by elevated urine homocysteine concentration. Test sent to Mayo Medical Laboratories.